In the piping facility industry, the technique of cutting a pipe or cutting and then beveling a pipe is one of the processes as important as a welding technique. In the past, gas cutting machines, saw machines and the like were used for pipe cutting and beveling. However, in recent years, as dedicated machines have been distributed, quality, workability, and productivity have been improved.
As illustrated in FIG. 1, a dedicated pipe cutting and beveling machine, which is currently distributed, includes a main body 2 configured to allow a pipe to pass therethrough and having a plurality of jaws 3 coupled so as to fix the pipe passing through the main body, a rotary plate 4 coupled to one side surface of the main body 2 and configured to orbit around the fixed pipe, and a cutter unit 8 coupled to the rotary plate and configured to cut the pipe. At this time, the cutter unit 8 is mounted on an entry adjustment plate 6 hinged to a point on the rotary plate 4 so as to pivot such that a cutting blade 9 is capable of entering toward or retreating from a cutting portion on the fixed pipe. Further, the pipe cutting and beveling machine includes an entry control unit 7 configured to move the entry adjustment plate 6 and a rotation control unit 5 configured to move the rotary plate 4.
The dedicated pipe cutting and beveling machine of the prior art configured as described above causes the rotary plate 4 to orbit one turn while cutting a portion of the pipe by the cutting blade 9, thereby cutting the pipe, or is capable of beveling the pipe by being equipped with a chamfering blade instead of the cutting blade.
The dedicated pipe cutting and beveling machine of the prior art has a structure in which the cutter unit 8 is separated from the entry adjustment plate 6 in order to replace the cutting blade or the chamfering blade. In order to prevent the cutter unit 8 from being inadvertently separated after being mounted, the dedicated pipe cutting and beveling machine has a structure in which the cutter unit 8 is inserted from the center to the outer peripheral edge side of the entry adjustment plate 6 in a slot type by a guide.
However, the cutter unit mounting structure described above has no problem in the standby state or in the state of preparing pipe cutting, but has a serious inconvenience in that it is necessary to remove the cutter unit in order to replace the cutting blade or the chamfering blade. A cutting blade replacing structure according to the prior art is briefly described. As illustrated in FIG. 2, the cutter unit 8 is configured to be separated from the entry adjustment plate 6 of the main body. At this time, in order to fix the cutter unit 6 tightly so as not to wobble, the cutter unit 6 is provided at the tip thereof with a concavo-convex-type mounting portion 11 such as a protrusion and a groove, and a concavo-convex-type guide 12 is also provided on the entry adjustment plate 8 corresponding to the cutter unit 6. Since the mounting unit 11 and the guide 12 have a structure of being coupled in a vertical slit type, so that they are configured to be inserted from above and fitted down.
Thus, in order to replace the cutting blade, it is necessary to lift the cutter unit 6. However, since the pipe p is fixed to the central portion of the rotary plate, the pipe p interferes with lifting the cutter unit 6. Thus, the replacement of the cutting blade is performed in the following order: {circle around (1)} extracting the pipe, {circle around (2)} separating the cutter unit, {circle around (3)} replacing the cutting blade from the separated cutter unit, {circle around (4)} coupling the cutter unit again, and {circle around (5)} fixing the pipe again. Therefore, in order to replace the cutting blade or the chamfering blade in the course of performing a work or in order to perform other work, it is necessary to remove the cutter unit in order to replace the cutting blade or the chamfering blade, which leads to a problem that the work efficiency and productivity are lowered.
On the other hand, there are problems in that the entry control unit 7 configured to cause the cutter unit 8 to enter or retreat to or from the pipe p side is not finely tuned after setting, that there occurs a phenomenon in which the entry adjustment plate 6 is slipped by the cutting load of the cutter unit 8, and that the proper fastening pressure of the entry adjustment plate 6 is not adjusted, and thus serious vibration is generated by the cutting blade.
That is, the operation method of the entry control unit 7 includes releasing a fastening tool 14, arbitrarily moving the entry adjustment plate 6 such that the cutting blade of the cutter unit 8 reaches a pipe cutting position, tightening the fastening tool 14 again to fix the entry adjustment plate 6 such that the entry adjustment plate is not moved, and turning the entry lever 13 downward so as to seat the entry lever 13 on the entry fixing pin (not illustrated). However, when there is an error in setting, it cannot be corrected in the set state, and it is necessary to perform the setting from the beginning again.
Since the entry adjustment plate 6 is fixed by the simple action of tightening or loosening the fastening tool 14, when the cutting load of the cutter unit 8 is slightly increased, there occurs a phenomenon in which the entry adjustment plate 6 slides from the fastening tool 14, which makes precise machining impossible.
In addition, the entry control unit 7 configured to control the entry adjustment plate 6 should have a proper clearance with the rotation plate 4 in order to smoothly control the entry adjustment plate 6. That is, when a large clearance is generated, a serious vibration is applied to the cutter unit 8 during operation, which significantly reduces the lifespans of equipment and the machining tools. When there is little clearance, a problem occurs in that the entry adjustment plate 6 cannot be controlled. However, a device capable of adjusting such a clearance has not been developed so far.